U.S. patent application number 13/207021 was filed with the patent office on 2012-03-01 for vehicle hub unit.
This patent application is currently assigned to JTEKT CORPORATION. Invention is credited to Naoto Araki, Katsuyuki Harada, Kentaro Shirakami.
Application Number | 20120049611 13/207021 |
Document ID | / |
Family ID | 44508980 |
Filed Date | 2012-03-01 |
United States Patent
Application |
20120049611 |
Kind Code |
A1 |
Harada; Katsuyuki ; et
al. |
March 1, 2012 |
VEHICLE HUB UNIT
Abstract
A vehicle hub unit includes: an outer ring; rolling elements; a
hub wheel that is arranged radially inward of the outer ring via
the rolling elements; and an inner ring member that is fixed to an
end portion of a hub spindle of the hub wheel by clinching. A
spline tooth portion that meshes with a tooth portion of a constant
velocity joint that transmits driving force to the hub unit is
formed at a clinched portion of the hub spindle. A protruding
portion is formed at a radially inner side portion of a bottom of
the spline tooth portion.
Inventors: |
Harada; Katsuyuki;
(Yamatokoriyama-shi, JP) ; Shirakami; Kentaro;
(Osaka-shi, JP) ; Araki; Naoto; (Yao-shi,
JP) |
Assignee: |
JTEKT CORPORATION
Osaka
JP
|
Family ID: |
44508980 |
Appl. No.: |
13/207021 |
Filed: |
August 10, 2011 |
Current U.S.
Class: |
301/109 |
Current CPC
Class: |
B60B 27/0036 20130101;
F16C 2326/02 20130101; F16C 19/186 20130101; F16C 35/063 20130101;
F16D 1/076 20130101; B60B 27/0094 20130101 |
Class at
Publication: |
301/109 |
International
Class: |
B60B 27/00 20060101
B60B027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 30, 2010 |
JP |
2010-192540 |
Claims
1. A vehicle hub unit comprising: an outer ring; rolling elements;
a hub wheel that is arranged radially inward of the outer ring via
the rolling elements; and an inner ring member that is fixed to an
end portion of a hub spindle of the hub wheel by clinching, wherein
a spline tooth portion that meshes with a tooth portion of a
constant velocity joint that transmits driving force to the hub
unit is formed at a clinched portion of the hub spindle, and a
protruding portion is formed at a radially inner side portion of a
bottom of the spline tooth portion.
2. The vehicle hub unit according to claim 1, wherein a height of
the protruding portion is set to such a height that a predetermined
clearance is left between the protruding portion and a top surface
of a tooth of the tooth portion of the constant velocity joint.
3. The vehicle hub unit according to claim 2, wherein the
predetermined clearance is 0.5 to 1 mm.
4. The vehicle hub unit according to claim 1, wherein the
protruding portion is formed radially inward of a meshing portion
at which the spline tooth portion is in mesh with the tooth portion
of the constant velocity joint.
5. The vehicle hub unit according to claim 2, wherein the
protruding portion is formed radially inward of a meshing portion
at which the spline tooth portion is in mesh with the tooth portion
of the constant velocity joint.
6. The vehicle hub unit according to claim 3, wherein the
protruding portion is formed radially inward of a meshing portion
at which the spline tooth portion is in mesh with the tooth portion
of the constant velocity joint.
7. The vehicle hub unit according to claim 1, wherein a portion of
the top surface of the tooth of the spline tooth portion, the
portion being near a radially inner end portion, is flush with a
radially inner inclined surface of the protruding portion.
8. The vehicle hub unit according to claim 2, wherein a portion of
the top surface of the tooth of the spline tooth portion, the
portion being near a radially inner end portion, is flush with a
radially inner inclined surface of the protruding portion.
9. The vehicle hub unit according to claim 3, wherein a portion of
the top surface of the tooth of the spline tooth portion, the
portion being near a radially inner end portion, is flush with a
radially inner inclined surface of the protruding portion.
10. The vehicle hub unit according to claim 4, wherein a portion of
the top surface of the tooth of the spline tooth portion, the
portion being near a radially inner end portion, is flush with a
radially inner inclined surface of the protruding portion.
11. The vehicle hub unit according to claim 5, wherein a portion of
the top surface of the tooth of the spline tooth portion, the
portion being near a radially inner end portion, is flush with a
radially inner inclined surface of the protruding portion.
12. The vehicle hub unit according to claim 6, wherein a portion of
the top surface of the tooth of the spline tooth portion, the
portion being near a radially inner end portion, is flush with a
radially inner inclined surface of the protruding portion.
Description
INCORPORATION BY REFERENCE
[0001] The disclosure of Japanese Patent Application No.
2010-192540 filed on Aug. 30, 2010, including the specification,
drawings and abstract, is incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a vehicle hub unit in which a
member that constitutes an inner ring is fixed by clinching to an
end portion of a hub spindle of a hub wheel to which a wheel is
fitted.
[0004] 2. Description of Related Art
[0005] A hub unit is used to support a wheel of an automobile such
that the wheel is rotatable with respect to a suspension. FIG. 4 is
a sectional view that illustrates an example of an existing hub
unit.
[0006] A hub unit 51 shown in FIG. 4 includes a hub wheel 53, an
inner ring member 54, an outer ring 55, and a plurality of rolling
elements 56. The hub wheel 53 has a hub spindle 52. The inner ring
member 54 is fixed to one end of the hub spindle 52 by clinching.
The outer ring 55 is arranged radially outward of the hub spindle
52. The rolling elements 56 are rollably arranged between one of
outer ring raceways 55a of the inner peripheral surface of the
outer ring 55, and an inner ring raceway 52a of the outer
peripheral surface of the hub spindle 52 or an inner ring raceway
54a of the outer peripheral surface of the inner ring member 54. A
flange portion 57 is formed at an end portion (left end portion in
FIG. 4) of the hub wheel 53, and a wheel of a tire, a brake disc,
and the like (not shown), are fitted to the flange portion 57. A
fixing flange 58 is formed on the outer peripheral surface of the
outer ring 55. In addition, the fixing flange 58 is used to fit the
hub unit 51 to a vehicle body-side member (not shown) supported by
a suspension of a vehicle.
[0007] Rotational driving force of a drive shaft 60 is transmitted
to the hub unit 51 via a constant velocity joint 59. As one method
of transmitting the rotational driving force, there is known a
method in which, as shown in FIG. 5 in detail, a spline tooth
portion (side face spline) 62 is formed at a clinched portion 61 of
the hub spindle end portion for fixing the inner ring member 54,
and then the spline tooth portion 62 is meshed with a tooth portion
(side face spline) 64 formed at an end surface of the outer ring 63
of the constant velocity joint 59 (see, for example, Published
Japanese Translation of PCT Application No. 2008-536737 and
Japanese Patent Application Publication No. 2008-174178).
[0008] In the hub units described in Published Japanese Translation
of PCT Application No. 2008-536737 and Japanese Patent Application
Publication No. 2008-174178, rotational driving force is
transmitted to the hub unit via a constant velocity joint due to
the mesh of the teeth that extend in a direction substantially
perpendicular to a rotary shaft.
SUMMARY OF THE INVENTION
[0009] It is an object of the invention to provide a vehicle hub
unit to which rotational driving force is transmitted via the
above-described side face spline, and in which stiffness of a
spline tooth portion formed at a clinched portion of a hub spindle
end portion is increased to thereby make it possible to increase an
allowable loading torque for the hub unit.
[0010] An aspect of the invention relates to a vehicle hub unit
including: an outer ring; rolling elements; a hub wheel that is
arranged radially inward of the outer ring via the rolling
elements; and an inner ring member that is fixed to an end portion
of a hub spindle of the hub wheel by clinching. A spline tooth
portion that meshes with a tooth portion of a constant velocity
joint that transmits driving force to the hub unit is formed at a
clinched portion of the hub spindle. A protruding portion is formed
at a radially inner side portion of a bottom of the spline tooth
portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Features, advantages, and technical and industrial
significance of exemplary embodiments of the invention will be
described below with reference to the accompanying drawings, in
which like numerals denote like elements, and wherein:
[0012] FIG. 1 is a sectional view that illustrates a vehicle hub
unit according to an embodiment of the invention;
[0013] FIG. 2 is an enlarged view that illustrates an end portion
of a clinched portion of the vehicle hub unit shown in FIG. 1;
[0014] FIG. 3A and FIG. 3B are views that illustrate a die for
clinching an end portion of a hub spindle and for forming a spline
tooth portion at the end portion;
[0015] FIG. 4 is a sectional view that illustrates an example of an
existing vehicle hub unit; and
[0016] FIG. 5 is an enlarged view that illustrates an end portion
of a clinched portion of the vehicle hub unit shown in FIG. 4.
DETAILED DESCRIPTION OF EMBODIMENTS
[0017] Hereinafter, a vehicle hub unit according to an embodiment
of the invention will be described in detail with reference to the
accompanying drawings. FIG. 1 is a sectional view that illustrates
a vehicle hub unit 1 according to the embodiment of the invention.
FIG. 2 is an enlarged view that illustrates an end portion of a
clinched portion of the vehicle hub unit shown in FIG. 1.
[0018] The vehicle hub unit 1 supports a wheel of an automobile
such that the wheel is rotatable with respect to a suspension. The
vehicle hub unit 1 includes a hub wheel 3, an inner ring member 4,
an outer ring 5 and a plurality of rolling elements 6. The hub
wheel 3 has a cylindrical hub spindle 2. The inner ring member 4 is
fixed to one end (right end portion in FIG. 1) of the hub spindle 2
by clinching. The outer ring 5 is arranged radially outward of the
hub spindle 2. The rolling elements 6 each are rollably arranged
between an outer ring raceway 5a of the inner peripheral surface of
the outer ring 5 and an inner ring raceway 2a of the outer
peripheral surface of the hub spindle 2 or between an outer ring
raceway 5b of the inner peripheral surface of the outer ring 5 and
an inner ring raceway 4a of the outer peripheral surface of an
inner ring member 4. The rolling elements 6 are retained by a cage
20, and arranged at predetermined intervals in the circumferential
direction. Seal members 21 are provided in an annular space formed
between the outer ring 5 and the hub wheel 3. The seal members 21
close the annular space from both ends of the annular space in the
axial direction.
[0019] A flange portion 7 is formed at the end portion (left end
portion in FIG. 1) of the hub wheel 3. A wheel of a tire, a brake
disc, and the like (not shown), are fitted to the flange portion 7
with bolts. A fixing flange 8 is formed on the outer peripheral
surface of the outer ring 5. The fixing flange 8 is used to fit the
hub unit 1 to a vehicle body-side member (not shown) supported by
the suspension of a vehicle.
[0020] The hub spindle 2 is a single-piece member that has a
large-diameter portion 9 and a small-diameter portion 11. The
large-diameter portion 9 is formed at a position near the flange
portion 7. The small-diameter portion 11 is smaller in diameter
than the large-diameter portion 9, and is formed so as to be
contiguous with the large-diameter portion 9 via a step 10. The
inner ring raceway 2a is formed in the outer peripheral surface of
the large-diameter portion 9. The inner ring raceway 2a corresponds
to the outer ring raceway 5a of the outer ring 5.
[0021] The inner ring member 4 is fitted onto the outer peripheral
surface of the small-diameter portion 11 of the hub spindle 2, and
then an end portion of the small-diameter portion 11 is clinched to
form a clinched portion 12. In this way, the inner ring member 4 is
fixed between the step 10 and the clinched portion 12.
[0022] Driving force of a drive shaft 31 is transmitted to the hub
unit 1 via a constant velocity joint 30. The constant velocity
joint 30 according to the embodiment is a Birfield constant
velocity joint. The constant velocity joint 30 includes an inner
ring 32, a plurality of balls 34 and a cage 35. The inner ring 32
is joined to one end of the drive shaft 31. An outer ring 33 is
arranged radially outward of the inner ring 32. The balls 34 are
arranged between the inner ring 32 and the outer ring 33. The cage
35 retains the balls 34.
[0023] The outer ring 33 of the constant velocity joint 30 has a
bowl-shaped outer ring cylindrical portion 33a and an outer ring
shaft portion 33b. The outer ring shaft portion 33b extends from a
center portion of an end surface of the outer ring cylindrical
portion 33a. The outer ring shaft portion 33b has a hole 36 that
extends in the axial direction. The inner peripheral surface of the
outer ring shaft portion 33b, which defines the hole 36, has an
internal thread. The hub unit 1 is connected to the constant
velocity joint 30 by a cap bolt 38 that has an external thread 37
at its end portion.
[0024] As shown in FIG. 2, a spline tooth portion 13 is formed at
the end surface of the clinched portion 12 of the end portion of
the hub spindle 2. A tooth portion 14 is formed at the end surface
of the outer ring cylindrical portion 33a, which faces the clinched
portion 12. Owing to the mesh of the spline tooth portion 13 and
the tooth portion 14, rotational driving force of the drive shaft
31 is transmitted to the hub unit 1 via the constant velocity joint
30.
[0025] 1 The number of teeth 13a of the spline tooth portion 13 is
37, a protruding portion 15 is formed at each bottom 13b between
the consecutive teeth 13a. Each protruding portion 15 protrudes
toward the tooth portion 14 of the outer ring cylindrical portion
33a that faces the spline tooth portion 13. Each protruding portion
15 is formed at a radially inner portion of the bottom 13b of the
spline tooth portion 13. More specifically, each protruding portion
15 is formed at the bottom 13b at a portion substantially radially
inward of a meshing portion 16 (hatched portion in FIG. 2) at which
the tooth 13a of the spline tooth portion 13 is in mesh with a
tooth 14a of the tooth portion 14 of the outer ring cylindrical
portion 33a. By forming the protruding portions 15, the stiffness
of each of the teeth 13a that constitute the spline tooth portion
13 is increased. Thus, the allowable loading torque for the hub
unit 1 is increased. For example, the experiment was conducted on
the spline tooth portion having 37 teeth, and the maximum principal
stress and the shear stress were respectively reduced by
approximately 14% and approximately 24% in the case where the
protruding portions 15 are formed as compared with the case where
no protruding portions 15 are formed.
[0026] A predetermined clearance C1 is left between each bottom 13b
of the spline tooth portion 13, including the surface of the
protruding portion 15, and a top surface 14c of the tooth 14a of
the tooth portion 14 of the outer ring cylindrical portion 33a,
which faces the bottom 13b. On the other hand, a predetermined
clearance C2 is left between a top surface 13e of each tooth 13a of
the spline tooth portion 13 and a bottom 14b of the tooth portion
14 of the outer ring cylindrical portion 33a, which faces the top
surface 13e.
[0027] The spline tooth portion 13 is formed together with the
clinched portion 12 at the same time by fitting the inner ring
member 4 onto the outer peripheral surface of the small-diameter
portion 11 of the hub spindle 2 and then subjecting the end portion
of the small-diameter portion 11 to closed die forging. In the
present embodiment, a die 40 shown in FIG. 3 is inserted into the
opening of the hub wheel 3 at a portion to which the inner ring
member 4 is fitted, and then the die 40 is oscillated at a
predetermined inclination angle about an axis 40a to perform
ordinary oscillating clinching. Through the oscillating clinching,
the clinched portion 12 and the spline tooth portion 13 are formed.
At this time, a recess 41 having a shape corresponding to each
protruding portion 15 of the spline tooth portion 13 is formed
radially inward of each protruding portion 40b of the die 40, the
protruding portion 40b corresponding to the bottom of the spline
tooth portion 13. During closed die forging, the recesses 41 are
used to form the protruding portions 15 of the spline tooth portion
13.
[0028] The tooth portion 14 of the outer ring cylindrical portion
33a as well as the spline tooth portion 13 is formed by closed die
forging. The predetermined clearances C1 and C2 are set such that
tolerances in closed die forging are absorbed so as not to cause
contact between the teeth when the constant velocity joint 30 is
fitted to the hub unit 1. Although the clearances C1 and C2 vary
depending on the accuracy of closed die forging, the clearances C1
and C2 are usually approximately 0.5 to 1 mm.
[0029] In addition, a top surface 13c1 which is near the radially
inner end portion and which is a part of the strip-shaped top
surface 13e of each tooth 13a of the spline tooth portion 13 is
flush with a radially inner inclined surface 15a of the
corresponding protruding portion 15. Thus, it is possible to reduce
concentration of stress to thereby enhance the stiffness of the
teeth.
[0030] In addition, in the present embodiment, it is possible to
enhance the stiffness of the teeth by forming the protruding
portion 15 at each bottom 13b of the spline tooth portion 13, and,
in addition, it is possible to reduce stress loading on the die 40
by forming the protruding portions 15. That is, in the embodiment
shown in FIG. 1 and FIG. 2, spline formation is minimized to reduce
the area of the flat portion of each bottom as compared with the
existing example shown in FIG. 4 and FIG. 5. Therefore, it is
possible to reduce a load on the protruding portions 40b of the die
40 accordingly. Specifically, a die pressing force required to form
the spline tooth portion 13 is decreased by approximately 20% to
thereby make it possible to decrease stress loading on the die 40
(stress at the maximum stress portion) to a value at or below half
of the stress loading on the die 40 in the existing art.
[0031] The invention is not limited to the above-described
embodiment, and various modifications and changes may be made
within the scope of the appended claims. For example, in the above
described embodiment, a double row angular contact ball bearing is
used as the bearing of the hub unit; instead, another bearing, such
as a double row roller bearing, may be used.
[0032] In addition, in the above described embodiment, the number
of teeth of the spline tooth portion is 37; instead, the number of
teeth of the spline tooth portion may be other than 37 (for
example, 31). In addition, in the above-described embodiment, the
sectional shape of each protruding portion is a wavy shape.
Alternatively, another sectional shape, such as a semi-circular
shape and a trapezoidal shape, may be employed. In addition, in the
above-described embodiment, there is employed a third-generation
structure in which an inner ring raceway is directly formed in the
outer periphery of the hub spindle. Alternatively, a
first-generation or second-generation structure in which a pair of
inner rings is press-fitted onto a hub spindle may be employed.
* * * * *